Distribution and pharmacology of the enkephalins and related opiate peptides

Abstract

Hughes and his colleagues were the first to describe the structure of the enkephalins, two naturally occurring pentapeptides which have high affmity for the opiate receptor (Hughes et al., 1975). It has been pointed out that the structure of these peptides is related to that of β-lipotropin, a 91 amino acid hormone found in the pituitary gland. Moreover further peptides have now been described which have opiate activity and represent longer sequences of the C-terminal portion of β-lipotropin. These longer peptides are generally known as endorphins. The largest of these is β-endorphin which represents residues 61–91 of β-lipotropin. [Met5]-enkephalin actually represents residues 61–65 of β-lipotropin (Simantov and Snyder, 1976a; Lazarus et al., 1976; Cox et al., 1976; Bradbury et al.,1976a).